Thermal switch



May 3,1927. 1,627,519

R. c. MALCOM THERMAL SWITCH Filed May lO, 1926 2e ,ef

l NsuL/J non ATTCFNEY Patented May 3, 1927.

UNITED STATES BOBCOE CLYDE IALCI, 0F WICHITA, KANSAS.

'msnm swrrcn.

Application Med lay 10,

This invention relates to thermal switches and has for its object the provision -of a novel thermometer 'operated circuit closer adapted for 'use for a wide variety of purposes for closing the circuit through signal devices, alarms or any other electrically operated indicating or control means, the device acting in accordance with temperature variations.

An important and more specific object is the provision of a circuit closer embodying a column of mercury or other similar conducting material ada ted to rise under the expansive influence o? heat and adapted to engage against a succession of contacts whereby a circuit or circuits to signal or control devices may be controlled in accordance with temperature variations.

Another object of the invention is to provide a device of this character embodying a contact device longitudinally movable with respect to a thermometer tube and adapted to be engaged with a selected one of a series of contacts entering the same in position to be engaged by the column of mercury when the same .rises under the iniiuence of heat.

An additional object is to provide a thermal circuit closer of the character described which wili be simple and inexpensive in manufacture, easy to use, positive in action,

eiicient and durable in service, and a gen-- eral improvement in the art..

With the above and other objects and advantages in view, the invention consists in the details vof construction and the arrant; ment and combination of elements to hereinafter more fully described and claimed, and illustrated in the accompanying drawings, in which Figure 1 is a front elevation of the com plete device. O

Figure 2 is a longitudinal section taken on the line 2-2 of Figure 1, and

Fi re 3 is a detail cross section taken ony the line 3-3 of Figure 1.

Referring more particularly to the drawing, I have shown the device as comprsing a base 10 preferably of insulating material and 'having mounted thereon -a thermometer device including a bulb 11 preferably having a protective covering 12 of rubber or other insulating material, the thermometer device further including an elongated constricted cylindrical tube 13 which extends u wardly along 'the base and which has exten ing thereinto at spaced pomts a 1926. Serial No. 108,187.

plurality of metallic contact elements 14 which will of. course be engaged by the co1- umn of mercury 15 within the thermometer device, when the column rises under the inuence of heat,

It is of course clear that any suitable means may be provided for mounting the thermometer device upon the base, but In the present instance, I have illustrated a clip or bracket device 16 which embracingly engages the covering 12 and which is secured to the base. bviously, the base may be providedwith holes 17 or any other equivalent means'whereby securing elements may be utilized for effecting securing upon a stationary support, such details being entirely immateriai in so far as the scope of the invention is concerned. It is also preferable to provide a bracket device 18 mounted upon the base and embracingly engaging the cylindrical tube portion i3 of the thermometer structure for securing the same and preventing displacement of any of the parts.

Extend ng into the bulb i1 at the lower portion thereof is a contact or Wire or other conductor 19 which, of course, maires ciectrical contact with' the mass of mercury located within the tube and bulb. Any desired means ma be provided connected with this wire thoug in the present instance, the connection is sim ly disclosed as being an insulated wire, t e insuiated portion 20 thereof being located Within a depending fiange portion 21 of the protective coverin the bare wire itself being sealed into the bu b as clearly indicated.

Mounted uponthe base l0 at a point near the upper end of thethermometer tube 13 is al metallic bracket member 22 which is here shown as secured to the base and adapted to be contracted by means of a nut member 23 engaged upon a threaded .post 24. As a matter of fact, the threaded post may conu stitute the entire securing means 'for the bracket device in addition to acting as a means forl eiecting adjustment of the bracket. v

Slidably mounted within the bracket device 22 is a tubular covering 25 of insulating material Within which is located a metaliic tubularshell 26 slidably enga ed upon the thermometer tube 13 and a apted to be brought into engagement with a selected one of the contacts 14 extending 'thereinto The metallic member 26 terminates in a plug or head 27 carrying a securing screw or the like are 2% with which is connected one end of a conductor 29. Obviously, when the mercury i5 Within the bulb and tube rises and engages any one of the contacts 14, and this contact lei is engaged by the metallic membei' 26, the circuit will be closed to whatever device is connected with the apparatus.

is a matter of fact, it may be preferable to provide a series of graduations or indications 30 upon the base adjacent the various contact members le which extend into the thermometer tube, these various indications designating degrees of temperature.

ln the operation of the device, let it be assumed that it is desired to set the mecha nism so that the circuit will be closed when the 'temperature rises to 44:0 degrees. .in such a case, the nut member 23 is loosened so as to permit the assembled members 25 and 2o to be slid through the bracket device 22 so as to engage the Contact member i4 opposite the graduation 4:40. When this is done, it is quite apparent that there is nothing more necessary inasmuch as if the temperature rises tothis degree, 'the expansion of the mercury i5 within the bulb and tube Wilt cause the mercury column to come into engagement with the contact lei which is opposite the graduation del). When this is done, it is obvious that there will be nothing whatsoever to obstruct the flow of current through 4the device and through whatever alarm, signal or control mechanism is utilized in connection therewith. t is really believed that the construction, operation and adrantages will be readily apparent to one skilledv in the art without further explanation.

TWhile l have shown and described the preferred embodiment'of the invention, it shouid be understood that I reserve the right to make such changes in the form, construction and arrangement of parte as will not depart from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, l claim i. in a thermal circuit closer, a tube and bulb containing mercury and providing a nem/p19 thermometer, a protective covering of insu lating material for said bulb and adjacent portion of said tube, a flange formed on said protective covering, a conductor sealed into the thermometer and having electrical connection With the mercury therein at all times, said conductor having an insulated portion received in said flange, a plurality of contacts sealed into the tube and adapted to have contact with the mercury therein when the latter rises under the inuence of heat, a conducting member adapted to be brought into engagement with a selected one ot' said last mentioned contacts, said conducting member consisting of a headed cylindrical metallic shell slidably mounted about the tube, a supporting bracket, a coverin of insulating material for the shell mem er and being slidably arranged within said supporting bracket, and a conductor tired to said head.

2. In a thermal circuit closer, a'tube and a bulb containing mercury and providing a thermometer, a protective covering of insulating material for said bulb and adjacent portion of said tube, a flange formed on said protective covering, a conductor having an insulated portion received in said tiange, said conductor being sealed into the themometer and having electrical connection with 'the mercury therein at all times, contact means sealed into the tube and adapted to have contact With the mercury therein when the latter rises under the iniiuence ot' heat, a conducting member adapted to be brought into engagement with said contact means. said conducting member consisting of a cylindrical metallic shell member slidably mounted about the tube, a supporting bracket, a covering or" insulating material for 'the shell member, said covering carry ing the shell member. means included in said supporting bracket for engagement with the covering and for clamping theshell member with the Contact means, and a conductor fixed to said shell member.

lu testimony whereof I affix my signature.

ROSCGE CLYDE MALCOM. 

